Interatrial Septal Embryology

Interatrial Septal Embryology

1. Start of week 3: primitive streak is formed. Epiblast and hypoblast become ectoderm, mesoderm and endoderm

2. Middle of week 3: cardiac progenitor cells form primary heart field

3. Day 18/19: cells in the ectoderm differentiate to form the neural plate

4. Week 4: primary heart field undergoes vasculogenesis and then lateral folding to form the primary heart tube

5. Day 21: heart starts to beat

6. Day 24: heart starts to pump blood

7. Day 23: heart looping means primary heart field dilations form the correct communications

8. Day 27: septation involving the endocardial cushions occurs

9. Weeks 5-7: separation of common atria occurs forming septum primum and septum secundum